1. Field of the Invention
The present invention relates to a safety needle with a telescoping shield that is triggered during a standard sequence of operation of a medical procedure and, more particularly, relates to a needle and hub assembly having a telescoping shield that is triggered when an evacuated tube is mounted in the evacuated tube needle holder.
2. Background Description
An evacuated collection tube, needle and needle holder are commonly used by a doctor, phlebotomist or nurse to draw a sample of body fluid from a patient in a hospital or doctor's office for diagnostic testing. During the use of such a needle holder, the distal end of the needle in the needle holder is inserted in a vein of the patient. The evacuated collection tube is then inserted into the proximal end of the needle holder until a needle within the holder pierces a closure on the end of the tube. The vacuum in the tube then draws a body fluid sample from the patient through the needle and into the tube. After the collection process is complete the needle is removed from the vein and disposed of.
Because of the great concern that users of such needles may be contaminated with the blood of a patient by accidental sticks from the contaminated needle, it is preferable to cover the contaminated needle as soon as it is removed from the vein. For this reason, many developments have been made to provide means for covering the contaminated needle, once it is removed from the patient. These devices usually involve some sort of shield arrangement that moves in place over the contaminated needle once it has been removed from the patient. However, these shield arrangements have required the use of one or two hands to perform the operation of moving the shield over the contaminated needle, which is a hindrance to the user.
Alternatively, needles with internal or external blunting cannulas have been used that extend from the needle to blunt the distal end. However, these devices require an additional manual operation to drive the blunting cannula over or out of the needle upon completion of blood drawing to protect the user from the sharp end of the needle and also allow the user to draw blood without triggering the safety device. Such devices also require the internal diameter of the needle to be decreased which may affect blood flow or require the external diameter of the needle to be enlarged which may cause unnecessary discomfort to the patient.
Other needles have shields that are activated during the venipuncture operation when the shield comes in contact with the skin. Using the skin to activate the device is not desirable since the device may not activate if the needle does not penetrate sufficiently or may cause the shield to inadvertently lock when probing for the vein. Such devices may also require excessive penetration into some patients to cause the triggering means to activate the device which will cause a phlebotomist to unnecessarily have to change their standard method or procedure.